Site Specific Optimization of Rotor/Generator Sizing of Wind Turbines

Abstract

Economics, including all incentives, is the primary factor that drives the development of wind farms. Optimizing the wind turbine generator size-to-rotor size design based on an economic figure of merit shows that maximum wind turbine capacity factor does not yield the best economics for a given wind resource. A large rotor on a small generator will have a high capacity factor but a low annual output of electrical energy. For the same capital investment a different configuration would produce more electricity making the project more economically sound. This study varied rotor-to-generator size at a fixed capital cost and used a modified blade element momentum model to predict annual electrical energy production for each design at a given wind resource. Optimal design was the design that resulted in the highest annual electrical energy production. This was done at a series of fixed costs and a series of wind resources defined by the Weibull distribution parameters. The results indicated the following: At larger turbine sizes, (higher capital cost per turbine), the economics shifted toward a larger generator and smaller rotor (relatively). This exact relationship is dependent on the wind resource. At large turbine sizes, greater flexibility is shown in optimum generator sizing vs. rotor sizing. Having multiple generator size options for the same rotor size allows developers to more closely match and capitalize on the characteristics of their wind resource. The end result of the research is a set of diagrams developers can use to select the best turbine based on economics for their wind resource. This provides an additional tool they can use to make their projects more cost effective.

Fuzzy Logic Based Multi-Criteria Wind Turbine Selection Strategy—A Case Study of Qassim, Saudi Arabia

“…Martin et al [53] optimized the rotor-to-generator ratio for a hypothetical wind turbine using a range of wind conditions. However, it was stated that the approach can only serve as a support tool, rather than a complete selection method since many other important factors involved in the turbine selection process were not considered in the research.…”

“…Despite this, such approaches have been frequently used in the turbine selection problems [46,[48][49][50][51][52][53][54][55][56][57][59][60][61]64]. (5) Failure to account for impact of changing hub height on cost and production.…”

“…(2) Decision parameters that cannot be known by the developer. Most research papers assumed decision parameters for which information is not easily accessible (i.e., blade shape, product reliability, production volume, availability factors, organization of maintenance, system reliability indices, environmental issues, visual impact, political stability, among many others) [45][46][47][48][49][53][54][55][56][57][58][59][60][61][62][63]. Such parameters result in the selection approach being very complex and impractical.…”

“…(3) Restriction to a small variety of turbine types. Many research papers [47][48][49]53,54,56,58,[62][63][64] have used a small set of turbines type despite a huge variety of commercially available turbines. (4) Slow/inefficient optimization techniques (i.e., brute force calculations or iterative heuristics).…”

“…Majority of reviewed research [47][48][49][50][52][53][54][55]58] has been limited to using one decision criterion for the turbine selection process, which introduces limitations in the decision process. (2) Decision parameters that cannot be known by the developer.…”